Weed Eater One

Have had the weeeater one ride on about 2 and a half years, gone through 3 belts all replaced at the dealer/ service center where I bought mower. First time belt slipped off was within first 5 uses, last spring had to put belt back on over 10 times in the course of mowing just under an acre, my last mower never had this issue in the 15 years i owned it. Have given up taking it to dealer to have belt replaced, so tried to go there and buy the belt, after 2 visits there they are still unable to figure out which belt it is i need. What is the product or model number?
Another issue I have had is difficulty in maintaining an even cut height. Each time its been serviced deck has been leveled, and I have leveled it countless times but quickly it becomes unbalanced. For the price I was not expecting a professional grade machine but have been suprissed by the flimsiness, rattling and vibration of the mower and am embarassed i bought a machine that can not last a season without an issue
On positive side engine has been reliable, immediate start.